Retirement tax questions

Hello, thanks for the response!  I spoke with Vanguard this afternoon and the representative pointed out that I had contributed to SEP (employee contribution) and not SEP (employer contribution) for year 2018 in the amount of $686.00.  (I am a sole-proprietor with 1099 income).  This was reflected on form 5498 from Vanguard.  Due to my incorrect submission, Vanguard had listed my SEP employee contribution in box 1 under IRA contribution and not in box 8 as SEP contributions. Since, my AGI is above the limits of IRA eligibility, the representative had suggested to excess the SEP employee contribution listed in box 1 of 5498 for the amount of $686.00 and re-contribute the correct amount of $549 as SEP employer.  The deadline for SEP employer contribution is Oct 15, 2019.  Does that sound like the right advice? As per your response, I believe that if I rectify things in this manner then I do not need to amend the 2018 tax since the correct amount of $549 will be reconciled. I would just need to wait for the 1099 R from Vanguard and see if the distribution has to be filed in tax year 2018.